Asbestos-containing insulation on pipes, bar joists, valves, and other complex or irregular structures takes many forms, including chalky mixtures of magnesia and asbestos, preformed fibrous asbestos wrapping, asbestos fiber felt, corrogated paper, and insulating cement. In most cases, the insulating material is covered with a protective jacket (lagging) made of cloth, tape, paper, metal, or cement. Occasionally, asbestos millboard is used as outside lagging on removable insulating covers for stiffness. Lagging on pipes and boilers prevents spontaneous fiber release and helps protect against disturbance.
Removal of this asbestos-containing material has included the use of flat scrapers and wire brushes. This procedure has been found to be time-consuming and ineffective in thoroughly removing asbestos-containing material from complex and irregular structures because it is sometimes very difficult to access hard-to-reach portions of the irregular surface. Further, even with conventional surfaces, such as pipe and the like, conventional tools are often time-consuming and tiring for the operator because it is sometimes difficult to apply the scraping tool to the asbestos-covered surface.
When damage occurs to asbestos insulation and lagging on pipes and valves, removal of the material is essential in order to avoid the health hazard from potential contamination of the surrounding air by airborne asbestos fibers. To avoid exposure to airborne asbestos during asbestos removal operations, isolation protection systems, such as those disclosed in U.S. Pat. No. 4,626,291, entitled "Portable Containment Device for Treatment of Hazardous Materials", and U.S. Pat. No. 4,604,111, entitled "Particulate Contamination Control Method and Filtration Device", are used.